As is well known to those skilled in the art, aromatic hydrocarbons in middle distillate fuels such as gasoline or diesel oil represent a source of atmospheric pollution. The aromatic content of those middle distillates may be as high as 85 v %. An illustrative light straight run gas oil may for example be typically found to contain 30 v % aromatics. As environmental considerations become of greater concern, it is desirable to treat middle distillate hydrocarbons to decrease the content of undesirable aromatic components.
USP 3,997,473 (and its divisional USP 4,032,435) is directed to hydrodesulfurization of petroleum residues by use of a nickel/molybdenum on carbon catalyst which is characterized by an average pore radius of at least 25 .ANG. and a BET Surface area of 200-800 m.sup.2 /g. The catalyst of these patents has a loading of VI-B metal "of at least 10 and up to about 20 weight percent expressed as metal oxide based on the weight of the catalyst support."
USP 4,082,652 is directed to treatment of heavy oils, such as gas oils, to effect hydrodesulfurization by use of a molybdenum/nickel on carbon catalyst. The catalyst preparation requires that the molybdenum be deposited first then sulfided, and only then that the nickel be added.
USP 3,546, 103 is directed to the removal of metals and coke from hydrocarbon resids by use of, as precatalyst, metals of Group II-B or VI-B plus VIII on charcoal.
USP 3,367,862 is directed to desulfurization of heavy residual hydrocarbons by hydrolysis with water in the presence of catalyst on a char base.
USP 4,313,852 is directed to hydrotreating of heavy petroleum feedstocks in the presence of a sulfided molybdenum or tungsten on active carbon, with or without a second metalic component.
USP 3,725,303 is directed to treating of aqueous solutions of oxy-sulfur compounds (such as sodium thiosulfate) by use of a catalyst containing molybdenum sulfide and cobalt sulfide.
It is an object of this invention to provide a novel process for hydrodearomatizing middle distillate hydrocarbons. Other objects will be apparent to those skilled in the art.